Technical Field
The present invention relates to cooling and, more particularly, to pin fin compliant heat sinks having enhanced flexibility.
Description of the Related Art
Compliant heat sinks provide a good heat removal solution with low thermal resistance and substantially lower thermal interface stresses than standard, rigid heat sinks. Compliant heatsinks are able to conform to an irregular device surface without damage to the heatsink or to the device. In particular, pin fin compliant (PFC) and linked pin fin compliant (LPFC) heat sinks have favorable compliant performance at a relatively low cost.
PFC heat sinks include an array of pins between two compliant membranes. The PFC assembly is forced into contact with a device to be cooled using a compression layer. Small, local deviations from flatness are handled by PFCs with relatively low loads, as neighboring pins can move up and down relative to one another. Global deviations (such as a curved surface) can also be handled with sufficient loading, but the load needs to be high enough to bend the PFC heat sink as a whole. This puts one of the membranes in tension, resisting the bending. In the case of LPFC heat sinks, the links between individual pins also tend to resist bending. As such, standard PFC and LPFC heat sinks use high degrees of loading force when used on curved surfaces. These high loads create a risk of damage when installing or removing the heatsink, whether to the heatsink itself or to the device to be cooled.